Polishing slurry for cmp

Abstract

A polishing liquid for CMP has a composition loaded with, for example, an inorganic salt, a protective film forming agent and a surfactant capable of imparting a dissolution accelerating activity to enlarge a difference between polishing speed under non-load and polishing speed under load. By virtue of this polishing liquid for CMP, there can be simultaneously accomplished a speed increase for increasing CMP productivity, and wiring planarization for miniaturization and multilayer formation of wiring.

1 . A CMP method for copper using a polishing liquid, comprising polishing a copper surface with the polishing liquid, characterized in that the polishing liquid comprises at least one inorganic salt in a concentration of 0.01 M or more, which has an anionic species having an oxidation potential more positive than that of water, the anionic species being stable at the oxidation potential of water, a compound capable of forming an insoluble complex with copper, and a surfactant, wherein the concentration ratio of the compound capable of forming an insoluble complex with copper to the surfactant is 1/0.0001 to 1/0.4 by mol, or 1/0.0004 to 1/1.0 by weight, and wherein the polishing liquid comprises a solution at a pH of 3.0 or less. 
     
     
         2 . The CMP method for copper according to  claim 1 , wherein the polishing liquid further comprises a water-soluble polymer. 
     
     
         3 . The CMP method for copper according to  claim 1 , wherein the inorganic salt has a cationic species of at least one selected from the group consisting of potassium, sodium, ammonium, iron and aluminum. 
     
     
         4 . The CMP method for copper according to  claim 1 , wherein the compound capable of forming an insoluble complex with copper is at least one selected from the group consisting of benzotriazole, cupferron, salicylaldoxime, cysteine, aminobenzaldehyde, haloacetic acid, quinaldinic acid, benzoimidazole, benzoin oxime, anthranilic acid, nitrosonaphthol and oxine. 
     
     
         5 . The CMP method for copper according to  claim 1 , wherein the surfactant is dodecylbenzene sulfonic acid, potassium dodecyl sulfate, cetyltrimethylammonium bromide or sodium oleate. 
     
     
         6 . The CMP method for copper according to  claim 2 , wherein the water-soluble polymer is at least one selected from the group consisting of polyacrylic acid, polyvinylpyrrolidone, polyacrylamide, polyvinyl alcohol and poly-(4-vinylpyridine). 
     
     
         7 . The CMP method for copper according to  claim 1 , wherein the polishing liquid comprises a solution having a total ion concentration of 100 mM or more. 
     
     
         8 . The CMP method for copper according to  claim 1 , wherein Cu 2+  ions exist in a stable region of a pH-potential diagram. 
     
     
         9 . The CMP method for copper according to  claim 1 , wherein the polishing liquid can etch a rotating surface for CMP at an etching rate of 5 Å/min or less under non-load, and 500 Å/min or more under load. 
     
     
         10 . The CMP method for copper according to  claim 1 , wherein said at least one inorganic salt is selected from the group consisting of nitrates, sulfates, thiocyanates and oxo-acid salts. 
     
     
         11 . The CMP method for copper according to  claim 1 , wherein said at least one inorganic salt is selected from the group consisting of potassium nitrate, ammonium nitrate, aluminum nitrate, potassium thiocyanate, potassium sulfate, ammonium perchlorate, potassium perchlorate and aluminum perchlorate.